Engine-indicator.



No. 867,953. PATENTED OCT. 15, 1907.

T. DAVIDSON.

ENGINE mmcnoa.

APPLIOATIOX FILED D30. 12, 1008.

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UNITED STATES PATENT OFFICE.

THEODORE DAVIDSON, OF SALEM, MASSACHUSETTS, ASSIGNOR TO CROSBY STEAMGAGE AND VALVE COMPANY, OF BOSTON, MASSACHUSETTS, A CORPORATION OFMASSACHU- SETTS.

ENGINE-INDICATOR.

Specification of Letters Patent.

Patented Oct. 15, 1907.

To all whom it may concern:

13c it known that I, Tnnononn DAVIDSON, a citizen of the United States,and a resident of Salem, in the county of Essex and State ofMassachusetts, have invented certain new and useful Improvements inEngine-Indicators, of which the following is a specilication.

My invention relates to engine indicators and its object is to provide adrum furnished with a paper strip on which a series of diagrams may betaken without removing such strip from the drum and at such intervalsthereon as may be desired.

It is illustrated by the accompanying drawings in which- Figure 1 is anelevation of the drum with a portion of the indicator. Fig. 2 is acentral vertical section of the drum. Fig. 3 is top view of the drum.Fig. 4 is a section on the line H Fig. 1. Fig. 5 is a portion of thepaper strip with diagrams shown thereon. Fig. 6 is a detailed view inelevation of the cap. Fig. 7 is a detailed view showing the top of thecap. Fig. 8 is a central vertical section of the cap. Fig. 9 is asection on the line 9-9 Fig. 6.

Similar characters refer to similar parts throughout the severaldrawings.

1 is the indicator on which is mounted the pencil 2 movable towards andaway from the drum 3 and manipulated by the knob 4. On the arm 5 fixedto the indicator is mounted the fixed spindle 6 and on this spindle ismounted the rotary spring actuated drum 3 with a central opening at thetop and a vertical opening as shown. The drum actuating spring 7 is[ixed at its lower end to the springhead 8 fixed to said drum and at itsupper end to the springhead 9 fixed to said spindle. The cylindricalguard 10, having a cutout portion 11, is fixed to the upper part of thedrum adjacent to the central opening thereof and concentric therewithand is adapted to protect the paper strip or roll hereinafter mentioned.

On the upper end of the spindle 6 is mounted the cylindrical cap 12having a series of annular shoulders 13, 14 and 15. The cap isinteriorly squared at its lower end to engage the squared portion 16 ofthe spindle. Mounted in the cap is the spring-controlled catch 17adapted to engage the annular groove 18 on the spindle and suifieientlyyielding to permit the cap to be easily raised from or lowered upon thespindle. The exterior of the cap is graduated and numbered as shown(Fig. 6), and furnished at its outer edge with the vertical lug 19. Theannulus 20 is rotatably mounted upon the cap resting upon the shoulder13 and has a peripheral lug 21 adapted to engage the lug 19. Thisannulus is iurnish'ed with a binding screw 22 adapted to engage the capand prevent rotation of the annulus.

On the lug 21 is a mark 23 (Fig. 6) adapted to register with thenumbered marks on the cap above mentioned. A second rotary annulus 24:engages the cap, resting upon the shoulder 14 and the annulus 20, andhaving on its outer edge a vertical lug 25 adapted to. engage the lugs19 and 21.

On the outer end 01' the cap is rotatablymounted the knurled head 26resting upon the annulus 2i and shoulder ]5 and held in place verticallyby the screw 26". The lower part of this head constitutes a rotary cam27. The cylindrical sleeve 28 impending in the drum constitutesa reelwith its flanged top 29 resting upon the upper end of the drum. On topof the reel is fixed the ratchet 30 having outer teeth 31 and innerteeth 32. The reel has a knurled portion 33 for convenience in movingit.

Mounted on the upper end of the drum is the springcontrolled drivingpawl 34 adapted to engage the outer teeth of the ratchet and to be heldin or out of engage ment by the controlling spring 34" (Fig. 3). On theannulus 24 is mounted the spring-controlled retaining pawl 35 adapted toengage the inner teeth 01' the ratchet and to be thrown into and held insuch engagement by the controlling spring 35" (Fig. 2). This retainingpawl 35 engages also the rotary cam 27 employed to throw said pawl intoand out of engagement with the inner teeth of the ratchet and to hold itout of such engagement. These pawls, when engaging the ratchet, restupon the top of the reel and prevent its vertical movement. They preventindependent rotation of the reel in the direction indicated by the arrow36, but permit such rotation in the opposite direction indicated by thearrow 37.

The guide rolls 38 and 39 are arranged in the drum at its verticalopening and serve to guide the paper strip 40, which in the form of aroll is mounted upon the fixed spindle 4] arranged in said opening,passes around said drum and guide rolls and winds upon said reel asshown in Fig. i.

The inner edge of the paper strip is held against the reel by the spring42. The cord -13, fastened to the drum and encircling it, leadsthereirom between the guide pulleys 44 to a reducing mechanism or to thecrosshead of an engine in the usual manner. These guide pulleys arecarried on the arm 44 horizontally adjustably mounted upon the spindle6. The verti Cally adjustable arm 45 (Fig. 1) carries a pencil adaptedto mark upon the moving paper strip what is known as the atmosphericline.

From Figs. 6, 8 and 9 it appears that, when the parts are arranged astherein show u, the lug 25 of the rotary annulus 24 can travel onlybetween the lug 19 of the cap 12 and the lug 21 of the annulus 20 fixedin place by the binding screw 22.

The principal feature of my invention is the means for regulating thenumber of diagrams to be taken on a strip of given length or, in otherwords, for regulating the distance between the diagrams. This meansconsists of the combination of the cap 12 with the annuli 20 and 24, theannulus 20 being fixed and the annulus 24 (carrying the retaining pawlhaving a limited r0- tation between the lugs 19 and 21, all as abovedescribed. I

During this movement the retaining pawl 35 is carried around by itsfrictional engagement with the ratchet reel until the lug 25 engages thelug 19, after which the ratchet slips past the retaining pawl during theremainder of the forward stroke. Upon the return stroke of the enginethe drum is rotated by the spring 7 in the direction of the arrow 36 andcarries with it the reel and retaining pawl, all being held together byfriction, until the lug 25 engages the lug 21-, when the retaining pawlholds the ratchet reel stationary while the drum continues to rotate,the driving pawl slipping past the ratchet during the remainder of thereturn stroke. When the reel is moving with the drum the paper stripmoves with them, all practically as one;

' and when the drum is moving, while the reel is stationar-y, the paperstrip is wound off the spindle car ried by the drum and off the drumonto the reel. It is thus obvious that by determining the period of restof the reel we determine the amount of the paper strip which advancesaround the drum at each revolution of the engine and consequently thenumber of diagrams that can be taken upon a strip of; paper of a givenlength. All this depends upon the amount of travel allowed the retainingpawl and this is determined by the location of the adjustable lug 21.

By calculations it is found how many diagrams can be taken on a strip ofgiven length with the lug 21 adjusted at different distances from thelug l9 and the results .are marked upon the cap 12 (Fig. (i), so that inpractice the lug is adjusted with reference to these marks dependingupon, the number of diagrams desired. For instance, if the mark 23 uponthe lug 2]. registers with the number 300 on the cap, 300 diagrams canbe taken, etc.

As shown in Fig. 9 the lug 21 is adjusted with reference to lug 19, sothat approximately 100 diagrams could be taken on a paper stripmeasuring six feet, while in Fig. 6 the arrangement of the adjustablelug is such that 300 diagrams could be taken on a strip of that length.As described and shown, spring 7 rotates the drum around the stationaryreel during the latter part of the return stroke of the engine. To avoidputting this extra Work upon spring 7, the cord 43 may be so attached tothe reducing mechanism or to the crosshead of the engine that the engineshall, upon either stroke but preferably upon its return stroke, movethe drum. around the stationary reel, leaving the spring to move bothtogether, which is less work; an operation just the reverse of thatdescribed. This is, however,

merely a matter of detail or arrangement.

Having described my invention. what I. claim and desire to secure byLettersPatent is:

1. In an engine indicator the combination, with, the rotary drumsuitably mounted, of a reel upon which to wind a ribbon depending insaid drum, with adjustable means for intermittently and automaticallyrotating said reel a predetermined distance, said means comprising aratchet fixed to said reel, a driving pawl mounted on said drum and aretaining pawl suitably arranged and having a limited rotationsubstantially as described.

In an engine indicator the combination, with the rotary drum suitablymounted, of a reel upon which to Wind a ribbon depending centrally insaid drum, with adjustable means forintermittently and automaticallyrotating said, reel a predetermined distance, said means comprising aratchet fixed to said reel, :1 driving pawl mounted on said drum and aretaining pawl suitably arranged and having a limited. rotation;substantially as described.

3. In an engine indicator the combination, with the rotary drum suitablymounted, of a reel upon which to wind a ribbon, said reel being mountedin said drum concentrically therewith, with adjustable means forintermittently and automatically rotating said reel 21 predetermineddistance; substantially as described.-

In testimony whereof I have aflixed my signature, in presence of twowitnesses.

THEODORE DAVIDSON.

Witnesses HELEN M. DnAnBonN, RALPH W. FOSTER.

